The Australian started his career at APIA Leichhardt Tigers, a semi-professional club in New South Wales, Australia. Before turning professional, Nathan studied Business Administration at University.

As a youngster, Nathan played up front but switched to centre-back later on in his career.

Moulds joined Grays Athletic in the summer of 2006. However, he only played a few games for Grays, including a handful of pre-season friendlies, two starts in Grays’ Essex Senior Cup run and a substitute appearance in the FA Trophy at Weymouth. The 24-year old defender was released on 16th January 2007.